Cellulosic product



May 2, 1961 A. R. ELLIS EIAL CELLULOSIC PRODUCT Filed April 18, 1960 United States Patent ffiC 2,982,680 Patented May 2, 1961 CELLULOSIC PRODUCT Asher R. Ellis, Appleton, and Carl L. Broughton, Ncenah, Wis., assignors to Kimberly-Clark Corporation, Neenah, Wls., a corporation of Delaware Filed Apr. 18, 1960, Ser. No. 22,942

Claims. (Cl. 154-46) This invention relates to improvements in paper products, and more specifically to improvements in reinforced coverings for walls, billboards and the like.

A primary object of the invention is to provide an improved reinforced surface covering adapted to be adhesively bonded to a surface during use, but which may unitarily be stripped therefrom when replacement is desired, with only minor and easily removed portions thereof remaining on the surface.

A further object is to utilize a bonded fiber (nonwoven) reinforcing material in a wall covering of multiple laminate construction to gain substantially the strength and form-sustaining qualities of a fabric-backed wall covering at a substantially reduced cost of manufacture.

A still further object is to provide an improved reinforced wall covering including a relatively light weight laminated backing web adapted to be adhesively bonded to a surface during use but which readily delaminatcs from associated reinforcing and decorative plies as the latter are stripped as a unit from the surface prior to replacement of the covering.

Other objects and advantages will become readily apparent to persons skilled in the art upon examination of the description and drawings, as will various modifications of the structure without departure from the inventive concepts as defined in the appended claims.

in the drawings,

Figure l is a fragmentary plan view of a laminated wall covering the various laminations of which are shown broken away,

Figure 2 shows in fragmentary vertical section the wall covering of Figure l, and

Figure 3 is a greatly enlarged fragmentary section showing adhesive bonds between the piles and reinforcing element.

The problem of wall covering removal is a very old one, and while the more expensive type high grade coverings provided with a fabric backing may be stripped as a unit prior to re-hanging of a new covering, removal of the less expensive coverings has remained a problem of major concern to the industry. Low priced wall coverings, such as wallpaper, are seldom reinforced, and after application with paper hangers paste often resist being stripped from a wall to the extent that drastic measures such as scraping, dissolving, or steaming must be em ployed to clean the wall surface of old paper preparatory to a re-hanging operation. This is especially true of single-ply wallpaper as well as multiple-ply non-reinforced wallpaper. Since the high cost of fabric-backed wall coverings has resulted in limited use thereof as compared to the low and moderately priced non-backed types, a need has arisen for an improved moderately priced non-backed wall covering which is both reinforced and easy to remove. As is well known, reinforced wall coverings are superior to non-reinforced coverings in certain other respects, since they bridge and conceal minor wall defects, are easy to hang due to their internal strength, when hung present a surface texture indicative of a quality product, and in most instances require less frequent replacement than do non-reinforced coverings.

Figs. 1 and 2 illustrate a wall covering 10 incorporating a preferred embodiment of the invention. Covering 10 consists of an outer sheet 12 the exposed face 14 of which may be printed, coated, or otherwise treated to produce a desired decorative effect, as for example, the

design shown at 13, Fig. 1. The bottom surface of sheet 12 as shown has adhesively applied thereto a cross-laid non-woven reinforcing netting or scrim 16 which may consist of a set of warp threads 18 and a set of fill threads 20 extending across and engaging the warp threads 18. As shown in Fig. 1, the fill threads 20 may be disposed at substantial right angularity to the warp threads 18, or the fill threads may extend obliquely across the warp threads.

While element 16 is preferably non-woven, such mate rial sometimes being referred to as a bonded fabric, certain types of woven fabrics may be substituted therefor but usually only at an increased manufacturing cost without attendant advantages. A low cost non-woven netting particularly adapted for use as reinforcing element 16 is taught by recently issued Harwood Patent 2,900,980, assigned to applicants assignee. Such a netting consists of a set of warp threads or strands having a set of fill threads cross-laid thereon and bonded to the warp threads at the crossings. The threads may, for example, comprise several synthetic mono-filaments of a denier from l to 15 forming strands having a total denier of 30 to 130 with the strands being of low twist such as less than 6 turns per inch. When such a netting is subjected to pressure during roll application of an adhesive thereto the strands flatten out at the crossings to insure flexibility of the netting. in many respects such a cross-laid netting is superior to the more expensive woven nettings for the purpose herein taught. When coated with adhesive during fabrication of a wall covering incorporating the present invention, better bonding characteristics to adjacent layers may be obtained than when a woven fabric is employed as the reinforcing element. For example. netting 16 may be fabricated of threads consisting of i0 filaments of a high tenacity rayon, each filament being of 10 denier with the resultant threads of 100 denier. The invention, however, is not limited to the use of any particular type of netting or to the specific material or construction of the threads. Threads consisting of synthetic material such as rayon, Fortasan, glass, and Dacron are quite satisfactory.

Netting or scrim 16 is disposed, as best shown in Fig. 2, between outer sheet 12 and the innermost of a pair of contiguously associated creped wadding sheets 22 and 24. Outer sheet 12 to which a wallpaper pattern is applied is of a substantially heavier basis weight'than are the creped wadding sheets 22 and 24. Sheet 12 may be of known wallpaper stock consisting of 30% sulphitc and groundwood fibers, of a basis weight of 50 pounds per ream of 480 sheets measuring 24 inches by 36 inches. The exposed surface of the sheet is treated in the desired decorative manner as shown at 13, Fig. 1. Such treatment may include embossing, coating, lamina tion of a plastic or metal sheet thereon or various other decorative techniques. While sheet 12 may vary in con struction from the above example, it is important that the sheet be of suflicient basis weight and of such construction as to resist elongation thereof even when wet. as during a hanging operation, and sufilciently forrnsustaining when dry to retain a smooth surface appearance while bridging wall depressions and the like. Creped wadding sheets 22 and 24 may be of a basis weight of about 8 pounds per 3000 square feet which is somewhat heavier than facial tissue wadding, and about the weight of some table napkin stock. While the crepe ratio is not critical, a ratio between 1.05 and 2.3 has been found satisfactory. It is important, however, that at least one of sheets 2 and 24, and preferably both sheets, be creped to insure a relatively light bond therebetween by migrating adhesive during fabrication, and to minimize the bond therebetween resulting from migration of the fluid component of the wall paper paste during a hanging operation.

Known production methods may be employed for the high speed fabrication of wall coverings incorporating.

the invention. Prior to feeding scrim 16 between sheet 12 and multiple sheets 22 and 24, the scrim is roll or otherwise coated on both sides with an adhesive, it being important that enough adhesive is applied to the underside of scrim 16 as viewed in Fig. 2 tov permit a portion thereof to strike through creped wadding sheet 22 and migrate into creped wadding sheet 24, there being no other adhesive bond between those two sheets. While the type of adhesive employed is not critical, it must be of a fluidity to migrate in the manner shown in Fig. 3, and provide a very strong bond between the scrim 16 and adjacent sheets 12 and 22 plus a weaker bond between sheets 22 and 24. For example, certain polyvinyl chloride adhesives have been found satisfactory. The manner in which the adhesive, shown dotted in Fig. 3, migrates into the relatively heavy non-creped cover sheet 12 is illustrated, at 26, the migration thereof through the lighter weight creped wadding sheet 22 shown at 28, with limited adhesive migration into sheet 24 shown at 30. A secure adhesive bond is thus established between netting 16 and cover sheet 12 and between the netting and the adjacent creped wadding sheet 22, whereas a lesser or weaker adhesive bond is established between creped wadding sheets 22 and 24. While the adhesive thus transferred from the netting or scrim to adjacent sheets during fabrication of the wall covering may result in an interrupted rather than an unbroken linear application adjacent the warp and fill threads, the general adhesive pattern assumes the grid-like or other configuration of the netting from which the adhesive migrates into the various sheets.

During a hanging operation wallpaper paste is applied to the exposed surface of sheet 24 and fluid components of the paste migrate to some extent through creped wadding sheets 24 and 22, scrim 16, and to a lesser extent into facing sheet 12. The wallpaper paste employed is preferably of a viscosity to limit migration of fluid components into the associated layers, and when set, the bonds between creped wadding sheets 24 and 22, while strengthened by the paste, still remain substantially weaker than the bonds established by the more adherent adhesive applied during fabrication of the covering between scrim 18 and the immediately adjacent sheets 12 and 22. For some purposes, it has been found desirable to treat one or both sheets 24 and 22 with a wet strength resin or to otherwise treat them in a manner to minimize migration of the paste fiuid therein.

. Removal of the covering, after application to the wall surface in the above manner and after the wallpaper paste has completely set, may be easily effected by loosening a portion thereof and stripping the covering from the wall. Due to the adhesive bonds established as above described between the various elements comprising the covering, a separation occurs between creped wadding sheets 22 and 24 which are joined by the weakest bond, to permit facing sheet 12, scrim 16, and creped sheet 22 to be stripped from the wall as a unit. While adhesive is confined during the fabrication stage to a grid-like pattern as above described, those adhesive bonds are stronger, due to the type of adhesive employed, than are the bonds resulting from the migration of wallpaper paste through sheet 24, hence there may be some limited tearing of tissue sheet 24 in the immediate areas of the threads. Tissue sheet 24, a substantial portion of WhlCh remains glued to the wall after a stripping operation, may to some extent be mutilated by removal of fibers within the'grid-like pattern. Such depressions are minor in nature and a new covering may, if desired, be rehung over that sheet. If removal of the remaining portions of sheet 24 appears desirable prior to a rehanging operation, those grid-like depressions facilitate removal by a simple scraping operation.

Various modifications and adaptations of the concept herein taught will become readily apparent to persons familiar with the art. For example, while the inventive principles are illustrated as incorporated in decorative coverings for interior walls, the principles are equally applicable to billboard poster sheets to effect substantial savings in the cost of cleaning outdoor billboards after a plurality of posters have been applied thereto, one upon the other. The periodic scraping of a medium-size hillboard normally requires from 2 to 4 man hours of time. By surfacing a board with a covering fabricated as above taught, a plurality of poster sheets may be sequentially applied thereto in the usual manner. When removal is desired, the board may be cleaned in a fraction of the normal time by merely stripping the accumulated posters therefrom as sheets 22 and 24 separate. The board may then be re-covered with another backing element, to which a poster is then attached, or the first poster sheet so applied may have directly adhered to the back thereof the scrim 16 and the two creped wadding sheets 22 and 24 to provide a unitary assembly. As is well known in the trade, the water repellent characteristics of poster sheets as well as stain resisting and certain other types of internal wall coverings render their removal very difficult. The invention provides a means of easy removal for all types of coverings regardless of their water repellency or other characteristics which render their removal difiicult.

We claim:

l. A laminated surface covering comprising in combination, a cover sheet, a net-like reinforcing element, and multiple sheets of wadding, at least one of which is creped, said cover sheet being of substantially heavier basis weight than said sheets of wadding, said net-like element being adhesively bonded between said cover sheet and one of said sheets of wadding, said wadding sheets being adhered one to the other in a net-like pattern defined by the reinforcing element by a bond which is substantially weaker than the said bonds between the reinforcing element and the cover sheet and the immediately adjacent wadding sheet.

2. In a surface covering, the combination of a relatively heavy fibrous cover sheet, a laminated backing member consisting of two relatively light sheets of creped wadding, a net-like reinforcing element intermediate said cover sheet and said backing element, means forming a relatively strong adhesive bond between the element and the creped wadding sheet adjacent thereto, and means forming a relatively weak adhesive bond between the two creped wadding sheets.

3. The combination with a fibrous sheet-like surface covering, of a laminated backing structure adhesively bonded to one surface thereof for adhering said sheet to a surface while permitting delamination of said backing structure during a stripping operation, said structure comprising in combination a net-like fabric reinforcing ele ment adhesively bonded to the back surface of said cover sheet, and a pair of contiguously disposed inter-bonded creped fibrous sheets of lighter weight than said cover sheet forming a laminated backing element, one of said creped sheets being bonded to said reinforcing element, the adhesive bonds between said reinforcing element and said covering sheet and the creped sheet adjacent thereto being stronger than the adhesive bonds between said creped sheets.

4. A surface covering having in combination, a noncreped fibrous sheet, a net-like reinforcing element adhesively bonded to one side of said sheet, a pair of creped fibrous sheets of substantially less basis weight than said non-creped sheet, one creped sheet of said pair being maintained engaged with said reinforcing element by a relatively strong adhesive bond, said pair of ereped sheets being maintained engaged by an adhesive bond which is weaker than said first and second mentioned bonds.

5. A wall covering comprising a surface sheet consisting of about 30% sulphite fibers and about 70% groundwood fibers and of a basis weight of about 50 pounds per ream, a non-woven scrim comprising two sets of spaced low-twist strands each consisting ot a plurality of synthetic mono-filaments of about 1 to 15 denier with the strands totalling about 40 to 150 denier each, said strands being flattened at the crossings, a pair of contiguously engaged creped wadding sheets each of a basis weight of about 8 pounds per ream, means maintaining said scrim adhesively bonded to said surface sheet and to said contiguously engaged creped wadding sheet, and means adhesively bonding said creped wadding sheets one to the other, said first mentioned bond being substantially stronger than said last mentioned bond.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LAMINATED SURFACE COVERING COMPRISING IN COMBINATION, A COVER SHEET, A NET-LIKE REINFORCING ELEMENT, AND MULTIPLE SHEETS OF WADDING, AT LEAST ONE OF WHICH IS CREPED, SAID COVER SHEET BEING OF SUBSTANTIALLY HEAVIER BASIS WEIGHT THAN SAID SHEETS OF WADDING, SAID NET-LIKE ELEMENT BEING ADHENSIVELY BONDED BETWEEN SAID COVER SHEET AND ONE OF SAID SHEETS OF WADDING, SAID WADDING SHEETS BEING ADHERED ONE TO THE OTHER IN A NET-LIKE PATTERN DEFINED BY THE REINFORCING ELEMENT BY A BOND WHICH IS SUBSTANTIALLY WEAKER THAN THE SAID BONDS BETWEEN THE REINFORCING ELEMENT AND THE COVER SHEET AND THE IMMEDIATELY ADJACENT WADDING SHEET. 